Overvoltage or undervoltage action circuit

Due to its high precision, this circuit can be used in circuits or electrical equipment with strict operating voltage requirements. Its operating voltage only differs by 0.1 volt, as shown in the figure. For example, if the power supply voltage of the equipment is 12V and the circuit is connected, overvoltage action is required. As long as W is adjusted so that relay J does not operate at 12V, the breaker will close when the power supply voltage rises to 12.1V. On the other hand, if under-voltage action is required, just adjust W so that the relay just pulls in at 12V, and the relay will release when the power supply voltage drops to 11.9V. Use the action of the relay to turn on the alarm circuit or cut off the power supply. The operating voltage range and corresponding D1 voltage stabilization value can be found in the attached table. R1 should be adjusted appropriately when the operating voltage changes. If the power supply voltage is too high and the working voltage of the relay is low, a series of resistors can be used to solve the problem. Operating voltage range: 9～13V ---- 13V～18V D1 voltage regulation value: -- 7.5～9V ---- 9.5～12V